physiology renal 1

Question 1

function of kidney

Answer 1

1. maintain h20 and salt balance in body
2. maintain acid-base balance in the body
3. maintain plasma volume
4. Excreting the end products (wastes) of bodily metabolism and drug metabolites
5. Producing erythropoietin (rbc formation)
6. Producing renin

Question 2

Structures that carry urine from the kidneys to the outside for elimination
from the body

Answer 2

• Ureters
• Urinary bladder
• Urethra

Question 3

Ureters:
structure
exits each kidney..
function

Answer 3

• smooth muscle walled duct
• at the medial border, close to the renal art&vein
• carries urine to urinary bladder

Question 4

urinary bladder
structure
function

Answer 4

hollow smooth muscle

Temporarily stores urine

Question 5

Urethra
function
structure in females 
structure in males

Answer 5

• transports urine to out of the body
• short and straight
• much longer and follows a curving course …… Dual function: the elimination of urine from the bladder AND passageway of semen from reproductive organ

Question 6

The functional unit of the kidney:

Answer 6

THE NEPHRON

~1 million nephrons per kidney

Question 7

1. Each nephron has two components:

2. Arrangement of nephrons within kidney gives rise to two distinct regions:

Answer 7

Vascular component and tubular component

Outer region: the renal cortex
Inner region: the renal medulla

Question 8

glomerulus

function

Answer 8

filtering component of kidney

water and salts are filtered

Question 9

glomerulus

blood. pt1

Answer 9

from renal artery blood passes afferent arterioles which deliver blood to glomerulus

efferent transport blood from glomerulus

Question 10

glomerulus

blood pt2

Answer 10

efferent arterioles break down into peritubular capillaries which surrounds the tubular part of nephron

peritubular cap join into venules which transport blood to. the renal vein

Water and solutes are filtered through glomerulus as blood passes
through it

Question 11

Tubular component of nephron

Answer 11

hollow, fluid filled tube made up of single layer epithelial cells

Question 12

Tubular components

Answer 12

bowmans capsule
proximal tubule
loop of henle (descending. and asc. limb)
 Juxtaglomerular apparatus
distal tubule
collecting duct

Question 13

• Two types of nephrons

- defined by

Answer 13

• juxtamedullary and cortical nephrons

- length and location

Question 14

Basic renal processes (Glomerular filtration)

Answer 14

fluid filtered from glomerulus into bowmans capsule pass thru 3 layers of membrane:

• glomerular capillary wall
• basement membrane
• inner layer of bowmans capsule

Question 15

Glomerular capillary wall

Answer 15

single layer of endothelial cells

more permeable to water and solutes than capillaries else where in body

Question 16

Basement membrane

Answer 16

Acellular gelatinous layer

composed of collagen and gylcoproteins

Question 17

Inner layer of Bowman’s capsule

Answer 17

consists of podocytes that encircle the glomerulus tuft

Question 18

The glomerular filtration rate (GFR) is about

Answer 18

125 ml/min in a normal adult

Question 19

Glomerular Filtration:

Ultrafiltrate

Answer 19

cell and protein free

conc. of small solutes is the same as plasma

Question 20

a condition called proteinuria

Answer 20

in some diseases the - charge is on the filteration barrier is lost and so the proteins are more readily filtered

Question 21

Net filtration pressure =

Answer 21

The volume of plasma filtered through the glomerular capillaries into Bowman’s capsule per unit time

Question 22

Forces involved in glomerular filtration

if they favour or oppose filteration

Answer 22

–Glomerular capillary bp F
–Plasma-colloid osmotic pressure O
–Bowman’s capsule hydrostatic pressure O

Question 23

Renal blood flow (RBF)

• what % rbf is from cardiac output
• determines
• autoregulated between

Answer 23

• 25
• GFR
• 90 – 180 mmHg

Question 24

filteration is driven by

Answer 24

starlings forces across walls of glomerular caps

Question 25

Renal blood flow - autoregulation

Answer 25

uncouples renal function from arterial pressure and ensures that fluid and solute exceretion is constant

Question 26

Renal autoregulation 2 mechanisms

Answer 26

myogenic response

macula densa tubuloglomerular feedback (MD-TGF) response.

Question 27

Myogenic hypothesis

Answer 27

when arterial pressure ↑ the renal afferent arteriole is stretched and the flow↑

vascular smooth muscle contracts to ↑ resistance.
↑ of muscular tone makes the flow go back to normal

Question 28

Tubuloglomerular feedback

Answer 28

Alteration of tubular flow is sensed by macula densa of the juxtaglomerular apparatus (JGA)

produces a chemical signal that alters GFR

Question 29

Reabsorption:
what is reabsorbed
where

Answer 29

99% H2O
100% glucose, amino acids
99.5% Na+
50% urea.

proximal convoluted tubule.

Question 30

types of Tubular reabsorption

Answer 30

passive and active

Question 31

Passive reabsorption

Answer 31

no energy needed for substances net movements

occurs down electrochemical or osmotic gradients

Question 32

active reabsorption

Answer 32

occurs if any one of the steps in transepithelial transport of a substance requires energy

movements occurs against electrochemical gradient

Question 33

Sodium reabsorption

Answer 33

an active Na+ - K+ ATPase pump in basolateral membrane is needed for Na reabsorption

of total energy spent by kidneys , 80% is used for Na+ transport

water follows reabsorbed sodium by osmosis which has main effect on blood volume and blood pressure

Question 34

Tubular secretion
what
involves

Answer 34

transfer of substances from peritubular capillaries into the tubular lumen

transepithelial transport

Kidney tubules can selectively add some substances to
the substances already filtered

Question 35

Most important secretory systems are for:

Answer 35

H+
K+
Organic ions

Question 36

H+
function
secreted in

Answer 36

regulating acid base balance

proximal, distal, and collecting tubules

Question 37

K+
function
secreted in

Answer 37

keeps plasma K+ conc at right level to maintain normal membrane excitability in muscles and nerves

distal and collecting tubules under control of
aldosterone

Question 38

organic ions

Answer 38

accomplish more efficent elimination of foreign organic compounds from the body

promixal tubule